1. Technical Field
The present invention relates to antennas working in multiple frequency bands, and more particularly to a multi-frequency antenna working in multiple frequency bands.
2. Description of Related Art
With the development of communication technology, the ITU (International Telecommunication Union) loosened its official definition of 4G to include LTE (Long Term Evolution) in 2010. Prior patents related to LIE antennas include Taiwan Patent No. M391734, which has disclosed an LTE antenna structure comprising a circuit board, a monopole antenna, a coupling element, a metal stamping, a capacitor and a signal line. The monopole antenna and the coupling element are formed on the circuit board. The coupling component circles around the monopole antenna. The metal stamping is soldered to the periphery of the circuit board. The capacitor is coupled to the monopole antenna and the coupling element. The signal line has a ground wire connected to the coupling component and a signal feeding wire contacting the monopole antenna. Therein, the patented LTE antenna structure needs the capacitor for connecting the monopole antenna and the coupling component so as to attain impedance matching, but the capacitor undesirably thickens the overall antenna structure.